Notching Or Cutting Holes In Engineered Floor Joists

Home Inspector with Jay Markanich Real Estate Inspections, LLC

A popular construction material these days are floor I-beams, sometimes called "Engineered Floor Joists."  You have seen them.  They are convenient and easy to use.  But there are strict guidelines for notching or cutting holes in engineered floor joists.

From the side they look like a steel I-beam.  There is a top and bottom section, with a vertical member in between.  They utilize a lot of glue, which is why the fire department does not like them if they get too hot.  The glue melts!

There are strict guidelines for their installation, necessarily.  They are strong when left intact, and not so strong if cut improperly.  Hence the guidelines. 

These guidelines are based on codes imposed by Mother Nature.  She is a very strict disciplinarian.

But she also enforces her codes with impunity.

Just look at her!  Impunity I tell you!  Impunity means "exemption from punishment or consequences."  Go ahead, try to punish Mother Nature for her code enforcement!

These guidelines have been developed by engineers after much testing and analysis.  The local building codes are based on these criteria.


This diagram shows those guidelines.

The Moment Critical Zone is the only area that notches or holes should be cut.

If holes are cut at the edges, you see, the beams can shear off!

If cut at the bottoms and on the sides, you remove the beam's ability to bear weight.

But all three pieces, working together, are very, very strong.

The physics works.  That pleases Mother Nature.

This photo shows cuts made in consecutive beams to accommodate a metal HVAC duct. 

The cut holes are dead center in the beams.

They are fine!

Both Mother Nature and the local codes are pleased.

But what happens when the local code is met, but Mother Nature might not like it?

On this new construction the builder's answer to my pre-drywall inspection comment was, "It meets code.  We are only required to make changes when we are not code compliant."

In this case I am not so sure!

This is the next joist beside a load-bearing wall.  This stud wall is directly under another load-bearing wall above.  It is the wall between the kitchen and dining room.

This I-beam will be holding a long granite counter top and cabinets.  That hole on the left was cut in the wrong spot and they simply moved over and cut another one.  Yes, the hole is within the "zone" for such cuts.  But a large section of the center of this beam has been removed!  Do you think that affects its strength?

You can see also plumbing pipes along the top and a gas line on the bottom.  What if Mother Nature impugns this arrangement?  It's to the local code!  Is it to her code?

Dead load is the weight of the materials introduced and put into a house.  In this case it would be granite and kitchen cabinets and ceramic tile flooring. 

How much "live load" (that's the load that will be introduced after the dead load like from kitchen stuff) will be put in those cabinets by the occupants of this house?  My answer -- "dunno." 

How much live load will Mother Nature allow before cracking this beam?  My answer -- "dunno."

When I suggested all this to the builder, the answer was NOT surprising.  "Dunno."

Did they shore up that I-beam before the drywall was installed?  NO.  Why?  "It meets code."

Alrighty then!

My recommendation:  people are not smarter than Mother Nature.  Physics works unless a countervailing force overcomes it.  But even though we have learned to control gravity, somewhat, gravity is STILL in control.  And I remain concerned about the gravity of this installation.




Posted by

Jay Markanich Real Estate Inspections, LLC  

Based in Bristow, serving all of Northern Virginia.

Office (703) 330-6388   Cell (703) 585-7560


Re-Blogged 5 times:

Re-Blogged By Re-Blogged At
  1. Lenn Harley 08/26/2011 07:03 AM
  2. Daniel H. Fisher 08/26/2011 07:42 AM
  3. Chris Smith 08/26/2011 08:04 AM
  4. Justin Dibbs 08/26/2011 08:05 AM
  5. Barbara Todaro 08/26/2011 10:57 AM
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Chris Smith
Re/Max Chay Realty Inc., Brokerage - New Tecumseth, ON
South Simcoe, Caledon, King, Orangeville Real Esta

Jay, Notching any joist or support beam can have consequences, but engineered joists are should never be notched according to a course I took last fall. Great Post!

Aug 26, 2011 08:01 AM #8
Jay Markanich
Jay Markanich Real Estate Inspections, LLC - Bristow, VA
Home Inspector - servicing all Northern Virginia

All the materials they use now can handle granite loads Debbie, IF they are spaced properly (meaning closer together) and notched properly.  The supervisor on site is supposed to know that.  Key word - "supposed."

For sure Daniel.  But the builders already know all these things.  Calling the rep would be fine, but he will just say space it like this, notch it like that.  He would think coming out is busy work.

Chris - the diagram expresses the industry standard for notching.  If varied from, problems have to result!

Aug 26, 2011 08:33 AM #9
Charles Buell
Charles Buell Inspections Inc. - Seattle, WA
Seattle Home Inspector

Jay, of course all manufacturers are different but my "Silent Floor" TJI book, even on a TJI/55 x 16, says the maximum hole size is 12-3/4" square---appropriately located of course.  All that ductwork sure looks bigger than that.  What am I missing?

Aug 26, 2011 09:39 AM #10
John Mulkey - Waleska, GA
Housing Guru

Jay - Having used "Silent Floor" joists for several years, I'm well aware of their advantages and limitations. Unfortunately, unless you are standing there guiding the subcontractor--my strategy--you often wind up with improper cuts.

Aug 26, 2011 10:01 AM #11
Steven Cook
No Longer Processing Mortgages. - Tacoma, WA

Jay -- what a great picture of "mother nature".  Of course, you had other options, like Hurrican Irene, or the tsunami. But this one gets the point across well.  Have a great weekend!

Aug 26, 2011 02:43 PM #12
James Quarello
JRV Home Inspection Services, LLC - Wallingford, CT
Connecticut Home Inspector

Without looking at any specs that hole looks bigger than I can ever recall being allowed by any manufacturer. And code don't mean jack when it comes to manufactures specs. Builders, gotta love how they wrap themselves in their protective code blanket.

Aug 26, 2011 07:35 PM #13
Jay Markanich
Jay Markanich Real Estate Inspections, LLC - Bristow, VA
Home Inspector - servicing all Northern Virginia

Hi Shadow!  That trunk is 12x12".  You can kind of tell by the dryer vent used as an HVAC duct!  It's dead center too.  They cut that hole nearly exactly to the size of the trunk.  But not that big one beside!

John - in my opinion, why would you need to stand beside professionals to supervise something as simple as that?  Oh, my mistake - 7-11 construction!

Steven - I was going to use this one!  But she seems a bit too stern for a Mother Nature with enough schtick to impugn as she enforces!  She also looks like my second grade teacher!  I was home sick a lot...

Jim - I hate that.  I like to say, "So, you build your houses to a minimum standard?"  That always gets them.  I should sick Mother Nature on them.

I agree about the code.  When things are "engineered" that means that someone has his/her own specs!  If that isn't enough, there is always gravity.


Aug 26, 2011 07:49 PM #14
Tara Stone
NJ Estates & Stables - Frenchtown, NJ
NJ Estates and Stables

Hi Jay...really great's so scary to not know if the ibeams holding your house up are truely supportive or not..In your opinion what is the best type of beam to be looking for? Steel..wood..?

Thanks, Tara

Aug 26, 2011 08:57 PM #15
Jay Markanich
Jay Markanich Real Estate Inspections, LLC - Bristow, VA
Home Inspector - servicing all Northern Virginia

Tara - wood I-beams are fine when installed properly.  In the center of the house, in the basement, often it takes a steel beam to carry the load.  I have three steel beams in my house!  And bunches of floor I-beams!

Tell David he should open his Realty Group in Virginia!  You wanted me to open an office in NJ, but I couldn't afford the taxes!

Aug 26, 2011 09:11 PM #16
James Quarello
JRV Home Inspection Services, LLC - Wallingford, CT
Connecticut Home Inspector

More often than not manufactures specs supersede code. I bet Mr. Builder doesn't like to hear that either.

Aug 27, 2011 07:46 AM #17
Jay Markanich
Jay Markanich Real Estate Inspections, LLC - Bristow, VA
Home Inspector - servicing all Northern Virginia

Necessarily Jim, if the code is the minimum standard.  Does the engineer designing a product want it used in its lesser-capacity or least-ability circumstance?  But that is exactly what the builder does!  And is still "obeying the law."

Aug 27, 2011 08:04 AM #18
Gayle Rich-Boxman Fishhawk Lake Realtor (503)755-2905
Vernonia Realty - Vernonia, OR
"Your Gateway to the Lake" Birkenfeld Oregon

Jay, thankf for being an excellent inspector, a terrific writer and someone with a good sense of humor!  I thought maybe that was your mom--same hair--ha!!

Found you on Lenn's re-blog.

Aug 28, 2011 12:20 AM #19
Jim Mushinsky
Centsable Inspection - Framingham, MA

Well that's the way it always works.  Once the city/town building inspector completes their inspection report, the builder will not make any changes.

How did your buyer handle all the information?

I wonder if this house will end up in a law suit.  There was a recent law suit in MA, a beautiful house on Lovers Lane.  The newspaper story title reads "Family imprisoned in a home of horrors".  You can imagine how bad it got.  Part of the story reads "after a monthlong trial in Middlesex Superior Court in which they sued their contractor, broker, and seven others, the presiding judge made the rare decision... "


Aug 28, 2011 01:08 AM #20
Jay Markanich
Jay Markanich Real Estate Inspections, LLC - Bristow, VA
Home Inspector - servicing all Northern Virginia

Thanks Gayle.  I try to be instructive and have a little fun at the same time.  But it's true - go against Mother Nature!  No, not my mother.  She retained the same hairdo she had in the 50s for the rest of her life.  And gone for many decades now.

Jim - this was not the only thing to concern her.  We will have to see what the live load brings to the circumstance! 

Aug 28, 2011 04:03 AM #21
Robert Butler
Aspect Inspection - Montreal West Island, QC
Montreal Home Inspector | Aspect Inspection

Don't let all that gravity get you down Jay, after all you don't have to live there. Isn't that what the builders crews says?

Nice of you to put in that picture of your Mom though.:))

Aug 28, 2011 04:08 PM #22
Jay Markanich
Jay Markanich Real Estate Inspections, LLC - Bristow, VA
Home Inspector - servicing all Northern Virginia

Robert - what they forget to say is someone has to live there!  And that lady looks like a lot of fun, though not my mother!

Aug 28, 2011 04:13 PM #23
Reuben Saltzman
Structure Tech Home Inspections - Minneapolis, MN
Minneapolis Home Inspections

I'd be curious to hear what the manufacturer had to say about those holes.

Sep 01, 2011 09:44 PM #24
Jay Markanich
Jay Markanich Real Estate Inspections, LLC - Bristow, VA
Home Inspector - servicing all Northern Virginia

I typically don't contact manufacturers after home inspections Reubs! Do you?

Sep 01, 2011 09:47 PM #25
William Decker
Decker Home Services, LLC - Glencoe, IL

I, regularly, see things that are "code", but are just plain wrong.  Some times the codes are old and have not been revised, somtimes the product is new and the code has not caught up with it yet.  In all cases, the manufacturer's installation instructions will override local codes.

BUT....  To often, builders only see the local code requirements as their only requirement.  No attention to detail or continuing education.

In any case, all this boiles down to liability.  "Who will pay if someting goes wrong, and especially if someone gets hurt?"  That is the real bottom line.

I make sure, by my inspection and my report, that the person holding the liability is not me.  I write my report in such a way that I help my client to also not have the liability.  If the builder says that it is OK, then the builder holds the liability.  Unfortunately, many times the local municipality has liability immunity.  This is true everywhere in Illinois.

I had a new construction house, a couple of years ago, that used OSB I joists, like these.  The builder had the first floor partially built when it started to rain and these joists got wet.  The manufacturer's installation instructions state that they cannot get wet and I told the builder that (and even showed him the manufacturer's documentation) be he said it was OK.  I talked to the local code inspector, when he came by, as he also said they did not have to be replaced.  I wrote it into the report for my client, but the builder and the builder's agent told the client not to worry and that I was just "being too picky".  The client closed on the house.

9 moths later, I recieved a call from the client.  Seems that the floor under the kitchen had "sunk" (actually, partially collapsed).  I checked it out and found that the OSB webbing had delaminated and partially rotted (finished basement, so we had to open the ceiling).  No signs of any water damage source.  The joists had goten wet during initial construction.\

Long story short, the client sued everyone.  I got off because I had called it out.  The builder had to pay a small amount but relied on the contract which only required him to build to the local code standard.  The Village declared immunity.  The client's insurance disclaimed it because they said it was a "construction error".

So, the client ate the major costs.

DO NOT rely on local codes to protect you.

Hope this helps;

Aug 27, 2014 09:20 AM #26
Jay Markanich
Jay Markanich Real Estate Inspections, LLC - Bristow, VA
Home Inspector - servicing all Northern Virginia

Agreed Bill!  I often refer instead to Best Practices.  In fact, I started a Best Practices group here on AR.  Check it out!

(My post today about the attic access ladder was proclaimed by the county to meet code... ummm...)

Aug 27, 2014 10:05 AM #27
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Jay Markanich

Home Inspector - servicing all Northern Virginia

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